Why are you using pthread_mutex_lock instead of the fuse -s option?

The read-only pecl fuse wrapper uses the following:

```
/* Force FUSE callbacks to be single-threaded */
add_index_string(pzargv, argc, "-s", 1);
argc++;
```

Aside from this question I would just like to say that this extension is awesome! This is so useful it blows my mind away. Thanks a lot man!
